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The GPU

Asus chose to build the Poseidon platform around the GTX 780 rather than the GTX 780 Ti. At $600, the Poseidon is expensive — a vanilla GTX 780 goes for about $480 these days. Whether or not the card deserves the premium will depend partly on its overclocking capabilities. In the past, we’ve had good luck with water cooling graphics cards — Visiontek’s CryoVenom could hit 1250MHz from 947MHz stock thanks to water cooling. AMD’s R9 295 X2’s liquid cooler allowed the company to slightly increase the GPUs clockspeed compared to its single-core sibling. Nvidia’s air-cooled dual-GPU Titan Z, in contrast, runs at a markedly lower clock than a pair of Titan Blacks in order to keep its target power consumption and board temperature.

Asus ships the clock with a Turbo Mode of 1006MHz and a base clock of 954MHz. That’s up significantly from Nvidia’s reference, which sits at 863MHz with a 1002MHz base clock. Obviously, one of our goals was to take the chip higher — and to test whether water cooling would deliver more headroom.

Overclocking and temperatures

We tested a pair of Poseidon GTX 780 cards in SLI in both air and liquid mode. Under air and at stock speeds, the GPUs would hit their default maximum temperature of 78C and throttle back. Pushing the core clock upwards wasn’t very effective in air cooling without simultaneously adjusting the maximum temperature — the two cores would just throttle down more quickly.

Water cooling changed this significantly. With our water block installed, GPU temperatures topped out at 51C for the first card in the loop and 57C for the second after 30 minutes of OCCT looping. The sound, meanwhile, was practically nonexistent. One of the great advantages of water cooling is that the only thing you hear is a faint gurgle from the pump.

If we cranked the Poseidon’s fans up to full speed, we could improve cooling even more — at that point, GPU #1 fell to 49C while GPU2 dropped to 55C. These are reasonably good idle temperatures for a card — for a full-bore performance test, they’re excellent — and utterly silent.

One of the things that separates overclocking testing on air vs. water is that air overclocking tends to dramatically increase GPU temperatures. Water, in contrast, mostly doesn’t. If your cooling system is good enough to handle it, you won’t see much temperature deviation between a stock and overclocked configuration.

Unfortunately, our overclocking results simply weren’t as good as some of the other sites that reviewed the Poseidon have reported. Some reviewers reported that they were able to push their GPUs as high as 1300MHz, and while we hoped for such lofty heights, it wasn’t to be. We were forced to settle on a clock speed of 1150MHz (up from 1006) while the RAM ran at 6.3GHz effective clock (up from 6GHz). One of our cards could handle 1.2GHz and 6.6GHz memory, but the other couldn’t.

Total clock rate increase was 14% over Asus’ shipped stock and 33% above Nvidia baseline for the GPU cores and 10% for memory.

No that’s just a 4GB + 4GB card, you have just as much memory as with normal CF setup, and i wish they would stop calling those cards 8GB cards.

Otherwise i could also start calling my setup a 18GB setup.

LtMatt

Havor have you been drinking? :P

That my friend, is a single 290X with 8GB of memory. I know as a friend has a couple. Ask OCUK customer services, if you don’t believe me. :)

havor

Ooo i was reading you wrong, i was thinking you called a 295X2 a 8GB card.

And yeah ii am well aware of the card, but that card cost $1000 per card, and there are only 250 ever made, so even do it would technical be the best solution out there, i still am not willing to invest $4000 at once.

As i believe GTX 880 or 390X will come with more memory, and i can survive pretty well on 3 Titans till then, or the next gen after that.

LtMatt

No worries Havor. :)

Michael Vasovski

“but if there ware a 8GB 290X i would gladly trade them in”

Joel Hruska

I think the bigger point — outside the R9 295X2 / GTX 780 comparison — is that water cooling is going to become more common. I’m not saying enthusiasts will embrace the idea of self-built radiators en masse (it’s rather complicated to do that), but I think liquid cooling and AIB solutions are going to be the drop-in option of choice. At the highest end, we may see simple water cooling loops with sealed containers more along these lines.

The benefits are just too huge. If Nvidia gave enthusiasts more headroom to push frequencies and voltage, I think the 780 samples could’ve gone even farther — and these weren’t great ASICs to start with.

As for the R9, the CryoVenom R9 290 could nearly match the GTX 780 Ti. From 947MHz to 1250MHz is nothing to sneeze at — all while maintaining a temperature of less than 50C.

Oranji Juusu

All a vendor has to do is sell a flagship card with an CLWC solution and the market would go wild.

I’m also surprised a vendor hasn’t taken the 295X2 and upped the radiator to 240/280mm for a slight premium.

Phobos

Seems the gtx 780 wins in price vs the r9 295, otherwise they both perform very similar. I do wonder if you test them using vsync on, given how vsync on caps the frames at 60fps it does not put too much stress on the GPU’s making them run much cooler. If so how much of a difference in cooling will they get using water cooling?

Bryan_S

The 295×2 tended to dominate in Minimum frame rate as well as average. With just the average… this review is not very useful.

NoldorElf

It’s not as good as it seems. Certainly it does not give the flexibility as this review suggests.

Unfortunately, the tubing is made out of aluminum, making it questionable at best for watercooling. The Maximus VI Formula suffered from similar flaws. I would not want this in a loop because in 1-2 years, there will be serious issue with galvanic corrosion. It’s best to have a “no more aluminum” mentality for your loop.

A direct comparison I think would be a pair of 290X + a water cooling block in Crossfire, rather than the 295X2, which uses an AIO solution. The issue here is overclocking headroom. This generation, the 780Ti responded better to voltage than the 290X, but if you were to buy 2x 290X, you’d probably have more headroom than with 2x 780 Poseidon. Drawbacks to the 2x 290X are their higher power consumption.

All in all, with the 4gb of VRAM, I think the 2x 290X are a better buy, despite the higher power consumption, unless you play games that don’t scale well with CF but do scale well with SLI.

Taken alone, it’s not a bad product, but I would not use it for water cooling.

Joel Hruska

The R9 290 that I tested from CryVenom had amazing headroom but was also a handpicked, hand-tested SKU that the company pre-validates. I can’t use it to effectively compare against Asus, and of course 1-2 comparison cards don’t really tell us anything about performance distribution.

86james randy

wow GTX 780 SLI Water cool win again R9 295X2… by 5FPS… what about price ?

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